Presume these are just circuit tours ? Official reply from US Embassy says this is a 'working visit', so there may not be any opportunities to board.

Yes indeed. If they follow the same procedure as last year they take you once round clockwise then once round anti clockwise. Close enough to get decent photos of the aircraft positioned around the edge but nothing in the centre of the deck as it were.You have to be really 'special' to get on board so for us mere mortals there's not a lot of chance I'm afraid..